Elongated rods are used as structural members. A rod is used in, for example, a cutting tool such as a drill or an end mill, which includes an elongated cylindrical rod called a blank on which cutting edges are formed. A drill for boring holes may be a solid drill, which includes a rod having flutes extending from the tip cutting edges. The solid drill is used, for example, for boring holes on a substrate onto which electronic components are to be mounted.
For example, Patent Literature 1 describes a drill blank that has compositions varying either radially or longitudinally.